No lubricant in compression chamber. Uses PTFE rings, coated rotors, or dry running design.
Typical range
0.5–500 HP depending on technology
Best for
Food, pharma, electronics, breathing air, paint, anywhere oil contamination is unacceptable.
Components
- Self-lubricating piston rings (PTFE) or dry rotors
- Sealed bearings
- Intercooler
- Larger cooling system
Common issues
- Shorter ring life vs lubricated (1,500–3,000 hrs typical)
- Runs hotter — verify ventilation
- Higher noise level
Maintenance
- Replace piston rings / cup seals at OEM interval
- Verify intake filter clean — abrasives destroy rings fast